The invention relates to a process for simultaneous selective hydrogenation of diolefins and nitriles using a plurality of reactors or reactor zones.
There are known in the art processes and catalysts for hydrogenating unsaturated compounds in liquid hydrocarbon feedstocks. U.S. Pat. Nos. 4,152,351, 4,271,323 and 4,734,540 each disclose processes whereby particular elements of a hydrocarbon feedstock are hydrogenated.
It is particularly desirable to hydrogenate diolefin and nitrile contaminants which may be present in hydrocarbon feedstocks. During the course of treatment of feedstocks for hydrogenation of diolefins and nitriles, however, the catalysts employed in the process gradually become spent or deactivated. Conventionally, the catalyst must be withdrawn from the reaction bed or other apparatus used during treatment so as to replace and/or regenerate the catalyst. This results in significant delays of the hydrogenation process.
The need remains for a method or process of regenerating a spent or partially spent catalyst which reduces the delays of the hydrogenation process.
It is therefore the primary object of the present invention to provide a process for regenerating a hydrogenation catalyst.
It is a further object of the present invention to provide a process for regenerating a hydrogenation catalyst wherein the catalyst is regenerated in the hydrogenation reactor bed.
It is a still further object of the present invention to provide a process for regenerating a hydrogenation catalyst wherein the catalyst is regenerated to a substantial level with respect to original activity.
It is another object of the present invention to provide a process for treating a feedstock including diolefin and nitrile fractions, wherein the catalyst is regenerated in the reaction bed when deactivated to a certain level.
It is still another object of the present invention to provide a process for treating a feedstock such as an FCC feedstock in multiple reactor zones wherein the catalyst in one zone is regenerated while another zone is used to treat feedstock.
Other objects and advantages of the present invention will appear hereinbelow.